Apparatus for producing composite metal articles



Feb. 27, 1940. R K. op s 2,191,478

APPARATUS FOR PRODUCING COMPOSITE METAL ARTICLES Filed Aug. 26, 1938 2 Sheets-Sheet l INVENTOR ROBERT K. HOPKINS BY ATTORN EY Feb. 27, 1940. R. K. HOPKINS APPARATUS FOR PRODUCING COMPOSITE METAL ARTICLES Filed Aug. 26, 1938 2 Sheets-Sheet 2 FIG. 3

INVENTOR ROBERT K. HOPKINS FIG. 2

"BY OW ATTOR N EY Patented Feb. 27, 1940 UNITED STATES PATENT OFFICE APPARATUS FOR PRODUCING COMPQSITE lVIETAL ARTICLES Robert K. Hopkins, New York, N. Y., assignor to M. W. Kellogg 00.,

poration of Delaware New York, N. Y., a cor- Application August 26, 1938, Serial'No. 226,861

9 Claims.

. throughout between the molten metal and the solidified metal, electric current is discharged in the region of the juncture of the metals to melt a depth of the solidified metal so that fused metal is presented to the molten metal for union therewith. This result is obtained by employing one or more movable electrodes and so controlling their movement that a fused surface is constant- 'ly presented to the rising molten metal and complete union is uniformly obtained. To assure'a complete union the molten metal, as well as the electric discharge, is ma ntained under a blanket of flux which may initially be solid or molten.

In order to operate the novel method. successfully it is necessary that the electric discharge bear a constant position relation with respect to the rising level of'the molten metal. I accomplish this by raising the electrode, or electrodes,

and its, or their associated operating means with the ris ng level of the molten metal, This application is particularly directed to this feature of r the invention.

It is, therefore, the primary object of this in- ,vention to provide a method for forming metal bod es, and novel apparatus for carrying the method out in practice, in'which molten metal is united to solidified metal byelectrical discharge from the end of an electrode; the novel method and apparatus being such that a constant positional relation is maintained between the end of Fig. 2 illustrating a modified form of the apparatus.

The novel method of this invention may be employed'in the manufacture of metal bodies of substantially uniform composition throughout or it may be employed in the manufacture of composite bodies that include a base of one composition with one or more coatings of different composition, or different compositions. The bodies as manufactured may be in the form of finished articles or they may be in the form of intermediate articles orworkpieces such as ingots, slabs, billets, cylinders and the like, from which final articles may be produced by working operations such as forging, rolling, etc. The final articles may be produced in the form of fiat members such as slabs, plates, etc., or shaped members such as angles, channels and similar shaped forms, or

they may be produced as solid cylinders suchas.

larlyapplicable to the manufacture of bodies, I

such as ingots, of substantially uniform composition that include an outer shell of metal, work refined or cast, to which is united a core of cast metal; the metal defining the outer surface of the shell being in such condition and free from imperfections to such adegree that the body may be worked directly as formed. It is particularly advantageous to form alloy ingots, such as chrome steel, chrome-nickel steel, etc., in this manner as the amount of metal removed and the labor employed in removing imperfections inthe 1 surface of alloy ingots preparatory to working are excessive. 1

The novel method of this invention may also be used in the manufacture of coated articles of different sorts and of a wide range of compositions, The base metal may be carbon steel, iron or "any of 'the metals and alloys commonly used in the manufacture of machines, apparatus, ves-' sels, containers, structural members, etc. The cast metal may be of any ferrous or non-ferrous metals of alloys such asnhrome steel, manganese steel, chrome-nickel steel, Monel metal, etc., having corrosion, or oxidation, or wear, or other resisting property superior to that of the chosen base metal in the intended service. The composite articles produced by my novel method, be-

ing unitary structures are admirably suited to withstand the severest service conditions, as for instance, those encountered in the petroleum processing arts where corrosive mediums are handled at temperatures in excess of .1000" F. and under pressures in excess of 1000 .lbs. per square inch. The preferred base metal for this class of service will usually be plain carbon steel or low chrome-molybdenum carbon steel; the I coating metal for this class of service will usually be chrome steel, chrome-nickel steel, Monel metal,

etc. I

By depositing molten base metal within a solidified shell of alloy a composite body may be formed which can be used as such or can be converted by well known working operations into outside, lined bars, rods and tubes. When the molten base metal is deposited around a solidified alloy core a body is produced which can be worked into internally lined tubes. By depositing molten base metal between concentric solidified alloy shells, tubes that are lined both inside and outside may be produced. By depositing molten base metal against one face of an upright or substantially upright sheet, plate or slab of solidified alloy a slab is produced which can be worked in a well known manner to produce lined sheets o'r plates. If the molten base metal is deposited between two such alloy sheets,'plates, or slabs the resulting body can be converted into sheets or plates both majorsurfaces of which are defined by alloy.

In all of the above cases it should be evident that when desired or advantageous the base metal maybe in the solidified condition and the alloy deposited as moltenmetal.

To carry out my novel method thesolidified metal is placed in a mold which, though not necessarily, is preferably arranged to be cooled by a the circulation of a heat exchange medium, such the solidified metal and the molten metal.

character and its effect on the current discharge v assures a thorough union throughout between vthe metals. The flu may be molten or'solid as placed in the moldand quantities ofit, may be added as required during the operation.

The flux should be such that it will not liberate deleterious gas, either as to quantity or kind, underthe conditions of the operation. The flux, furthermore, should not remove substantial quantitles of desirable ingredients from the molten metal or add substantial quantities of undesirable ingredients to the molten metal but must flux out impurities. silicates in general, either simple or complex, or mixturesof silicates are satisfactory. Aluminates, titanates, and similar compounds are also satisfactory and maybe'used alone or in mixture with silicates. The flux may also include thinning compounds such as feldspar, and theiike. The fiux may consist of prefused reacted ingredients orfof calcined, sintered or dried unreacted ingredients. cates of the alkaline earths, calcium and magnesium being most commonly used, and the silicates of manganese, aluminum and iron are preferred as fluxes.

After the,fi'ux blanket has beenlaid the molten metal is deposited in the mold "beneath the blanket of flux so that it will rise against thesurface of the solidified metal to which-it is to be united. The molten metal-may be supplied At "present, sili- S "from various sources. Thus, .it may be supplied from agladle, by either top or bottom pouring, or it may be supplied from one or more consumable electrodes of proper composition, or it may be supplied in part from one of these sources and in part from the other.

Shortly before, or concurrently with, or shortly after, the deposition of the molten metal is begun electric current is discharged from the end of an electrode, or electrodes, to the region of the juncture of the metals tofuse a depth of the solidified-metal and to supply sufilcient heat to the adjacent molten metal to assure a complete union ofthe metals.v This electrode, or electrodes, may be non-consumable or-consumable. If consumable it is preferably of substantially the same composition as the molten metal; This electrode, or electrodes, isangularlydisposed to both the solidified metal surface and the' molten metal surface and may discharge against both at their juncture or against one or'the other adjacent their juncture, It is necessary, however,

that the di'schargebe so located that'a sufficient depth of the solidified metal be fused and sumcient heat supplied to the molten metal to assure the thorough union of the metals.

Since a thorough union is desired throughout, it is necessary that substantially the whole of the surfaceof the solidified metal, to which the molten metal is to be united, be subjected to the infiuence of the electric discharge. This is accomplished by affecting such relative movement between the electrode, or electrodes, and the surface that there is constantly presented a substantially continuous band of fused surface metal in the region of the level of the rising molten metal. When a single electrode is employed, or when a plurality of electrodes are employed that are not closely enough spaced to overlap the areas fused by them, the relative movement will include a by merely maintaining the electric discharge constant, in other cases cooling is additionally required, while in still other cases it may be necessary/to vary the energy of the discharge as the operation progresses.

Since the surface fusing electrode, or electrodes, is angularly disposed relative to both the solidified surface and the molten surface and the molten surface. is constantly rising it is necessary to raise the discharge end of the electrode, or electrodes, with the rising molten metal in order to maintain an electric discharge of predetermined character between the electrode, or electrodes,

and a predetermined point 'or zone of the metal surface or surfaces. This may be accomplished in various ways. Thus, when the mold is of constant cross section the'electrode, or electrodes, may be raised at the rate of rise of the molten metal. A more satisfactory way'of accomplishing this result, and the. way that is at present preferred is to employ a water cooled, non-consumable electrode, made of copper, tungsten, etc., as a pilot electrode. The pilot electrode is positioned substantially normal to the molten surfaceand is so mounted that its end is fixed rela-' tive to the discharge end of the surface fusing electrode. That is to say, the pilot electrode is fixedly positioned relative to and vertically movable with the welding head of the surface fusing electrode or some element thereof such as the contact nozzle, electrode feed wheels, etc., that by its vertical movement raises the end of the electrode. By discharging electric current from the ends of the pilot electrode against the surface of the molten metaland by vertically moving the pilot electrode as required to maintain the length of the discharge constant, the end of the surface fusing electrode is maintained in a fixed positional relation with the surface'of the molten metal. The arc length of the pilot electrode may be controlled manually or automatically. In the manual control the voltage of the discharge is indicated and the pilot electrode is manually raised to maintain the voltage indication substantially constant. In the automatic control any of the usual arc control arrangements may be associated with the circuit of the pilot electrode and these employed to control the operation of a motor that is arranged to raisethe electrodes and their associated mechanisms.

The apparatus of the drawings is particularly suited for carrying out the novel method and can be used both in the formation of metal bodies in which molten metal is deposited around a. cylinder of solidified metal, or, around or within a shell of solidified metal. The apparatus can equally well be used when the molten metal is deposited against a flat surfaced solidified metal body by merely eliminating or not using the ro tatable mold stand.

The apparatus of Figs. 1 and 2 is arranged for manual raising of the welding head while that of Fig. 3 is arranged for the automatic raising of the welding head; otherwise the showings and the apparatus of these figures are identical.

The welding head i0 is mounted for vertical movement relative to a frame ll. Frame II .isattached to platform I 2, see Fig. 2, which is 1 supported for horizontal movement back and terial supply devices, etc., which of themselves do not form a part of this nvention and have for this reason not been shown.

Adjacent the upper end of frame i l is supported, in suitable bearings, a shaft N that carries v at each of itsends a sprocket wheel IS. A similar shaft 20 and, sprocket wheels 2| are posi-.

tioned adjacent the lower end of frame H. A worm wheel 22 is provided on shaft 20 adjacent one of sprocket wheels '2l. Wheel 22 meshes with a'worm 23. In Figs. 1 and 2worm 23 is driven by handwheel 24 which is supported on frame ll, while in Fig. 3 worm 23 is carried at the endof the drive shaft of .a motor 25; Motor .25- is likewise supported on frame II and is of the vari-speed reversible type generally used.

for feeding welding electrodes. Chains 26 and 21 run over sprocket wheels l9 and 2|. One end of each of the chains is fastened .to the top of welding head It) while the'other end of each of the chains is fastened to the bottom of welding head l0. Thus by rotating hand-wheel 24 of Figs. 1 and 2 or by energizing motor 25 of Fig. 5, welding head Ill may be raised or lowered. Rollers 29 carried by welding head In and bearing on frame H, are provided to maintain welding head I0 against lateral movement and to facilitate the vertical movement thereof. 3

Welding head I0 is diagrammatically represented and is intended to include the current supply connections or generators, the feed motors, control arrangements, et'c., for the electrodes to be described hereinafter. Theelectrode feed motors, the control arrangements, etc included in head I0 maybe of any preferred kind, well known in the electric arc welding and the electric arc furnace arts, suited for the purpose. The elements constituting the head maybe of comparatively simple form as shown for instance in the Morton Patent No. 1,648,561 or they may be of more complicated form as shown for instance in the Kennedy et al. Patent No. 2,145,010. Since the invention is not dependent on any specific form of welding head no specific form of welding head is shown or described here. A panel 30 is attached to and depends from head l0. Panel 30 has mounted thereon apparatus elements to be hereinafter described.

Positioned beneath head Hlis a rotatable mold.

stand 3| in which is supported an annular shell 32 of solidified metal.

Adjacent one end of head Ill isa pair of guide rollers 33 that guide the surface fusing electrode 34 to the feed rollers 35 from whence it passes through contact and bending nozzle 26. Rollers 35 are operatedby a feed motor 31 that, as shown, is sup-ported from panel 30 adjacent nozzle 36. Motor 31 is controlled from are control arrangements of the usual sort to maintain an electric discharge from the end of electrode 34 of desired characteristics. Motor 31 is preferably located close tonozzle 36, as shown, to assure an uninterrupted feed. One side of the current supply is connected through cable 38 to nozzle 36, the other side is connected through cable 39 to ground cable 40.

By rotating shell32 electrode 34 will fuse a band of the surface of shell 32. "With shells of comparatively small diameter the fused band will be sufficiently continuous to assure a union throughout with molten metal 4|. vHowever,

when the size of the/shell increases a plurality of electrodes 34 may be necessary. Two electrodes 34 spaced 180 apart are shownin the drawings, however, when required a greater number-spaced apart as necessary, may be used.

Nozzle 36 as shown, bends electrode 34 from the vertical towards the surface of shell 32. The are control arrangements mentioned while they will be effective to maintain a substantially constant discharge will not maintain the end'of the electrode in a fixed positional relation with the rising level of molten metal 41 and the surface g 'of shell 32. 'Unless such fixed'positional relation is maintained the discharge will move so far away from the surface of shell 32, as to be in- -is providedfwith a passageway through which wateror similar medium may be circulated. The water is led to the body through valved -line 43 and returned through valved line 44. Electrode 42 is fastened to the end of rod 45 which is adjustably supported in brackets carried by head I0 and panel 30. Current may be supplied to electrode "42, from a suitable source through cable 46, the other side of the current source may be connected to ground cable 40 by-cable 41.

In the embodiment of Figs. 1 and 2 volt meter.

48 is provided on head ID to indicate the voltage of the'arc between electrode 42 and the molten metal, or whenv flux blanket 49 is molten, between electrode 42 and the molten flux. Thus, by manipulation of hand wheel 24 head l6 and all of the elements and mechanisms carried thereby may beraised as required to maintain a predetermined discharge at the end of electrode '42. This will necessarily maintain apredetermined distance between the end of electrode 34 and the molten metal. I

In the circuit of electrode of Fig. 3 are included are control arrangements that control the operation of motor 25. These are control arrangements may also be of any preferred kind suited for the purpose and for example may be of the character shown in the Morton Patent No. 1,648,561 or the Kennedy et a1. Patent No. 2,145,010. In this case motor 25 will operate to raise head l0 and all carried by .it as required to maintain the predetermined discharge from the end of electrode 42 and thus, maintain the end of electrode 34 a predetermined-distance from the molten metal.

Molten metal 4| may be supplied in whole or. in part from an external molten metal source such as a furnace, etc. Metal from such source, in the apparatus shown, is poured from ladle 56 through conduit 5| through flux 49. The molten metal may also be bottom poured, i. e, it may be poured through a suitable conduit that opens in the bottom of the mold.

Molten metal 4| may also be supplied in whole or in part from a plurality of consumable electrodes 52, only one being shown. Electrodes 52 may be solid' or hollow and of any preferred cross-section, if desired constituents of molten.

characteristics Current is supplied from a suitable source to contact nozzle 54 by cable 55. The

other side of the supply is connected to ground 7 cable by cable 56.

' Mold stand 3| includes a bottom support element 5! which carries a plurality of support rollers 60 and BI, two onlybeing shown. In the center of element 51 is provided a cavity into which is fitted thrust bearing 62 that supports hollow shaft 63 for rotation about a vertical axis. Shaft 63 is attached to cylindrical block 64 and has splined thereto ring gear 65. A bearing disc 66, against which rollers 66 bear, is also splined on shaft 63. Gear 61, that is driven bythe output shaft of transmission box 68, meshes with ring gear 65.- Transmission box 68 is preferably I of the multi-ratio type and is driven by motor 69. Block, 64 includes a contact ring 16, of

"Ground cable 40 is con- I enlarged at its upper end and communicates to the outside of block 64 by means of radial bore 13. A pipe I4 is concentrically located within bore 12 and the bore of shaft 63 and screws into block 64. Pipe 14 communicates to the outside of block 64 by means of a radial bore 15. The lower end of the bore of shaft63 is closed by a gland 16 that I surrounds a hollow fitting 11 through which pipe 14 extends. fixed against rotation and has a valved water exit line 18 screwed into it. Into the end of fitting I1 Fitting 11 is.

is screwed a second fitting 19 into which pipe 14 or similar medium may be circulated for the cooling of mold stand 3| and thus aid in the control of the penetration into the metal of shell 32. Passageways 82 need not be incorporated in mold 8| but in lieu thereof mold 8| may include a jacket through which the cooling medium is circulated. As shown the inlet of passageways 82 is connected to bore 15 by pipe 83 and the outlet of passageways 82 is connected to bore l3.by pipe 84.

I claim:

1. In apparatus of the character described, a surface fusingelectrode, means for directing said electrode toward a metal surface angularly disposed to the horizontal, means for depositing molten metal against said metal surface to progressively cover said surface, means for maintaining an electric discharge of desired characteristics between said electrode and the zone of the meeting line of said molten metal and said 'surface, a non-consumable electrode adapted to dischargeelectric current against said molten metal fixedly positioned relative to said directing means and vertically movable therewith, and means for r moving said non-consumable electrode and said directing means to maintain a discharge of substantially constant characteristics from the end of said non-consumable electrode and to mainsaid electrode and the surace of the molten metal. y I

3. Imapparatus of the character described, an

electrode, means for directing said electrode toward a metalsurface angularly disposed to'the horizontal, means for depositing molten metal to progressively cover said surface, means for maintaining a discharge of desired characteristics be-.

tween said electrode and the zone of the meeting line of the molten metal and said surface to fuse said surface, means for effecting movement between said electrode and said surface to fuse-a band of said surface, and means operative to vertically move said electrode to maintain a sub stantially fixed positional relation between the surface of the molten metal and the end of said electrode.

4. In apparatus of the character described, a rotatable mold, means for rotating said mold about a substantially vertical axis, said mold be- 1 zone of the meeting line of the molten metal and said surface, means for passing current to said electrode means,means for passing current to said mold,and means for maintaining said electrode means in a substantially fixed positional relation with the surface of the molten metal as it rises in said mold;

5. In apparatus of the character described, a consumable electrode adapted to deposit metal by electric discharge to progressively cover an angularly disposed metal surface, electrode means adapted to discharge electric current in the zone of the meeting line of the molten deposited metal and said metal surface to fuse metal of said surface and unite the metals, a non-consumable electrode adapted to discharge electric current against the surface of the molten metal, said consumable electrode, saidelectrode means and said non-consumable electrode. being mounted for unitary vertical movement, and means for moving said consumable electrode, said electrode means and said non-consumable electrode vertically as a unit to maintain a predetermined distance between said non-consumable electrode and the surface of the molten metal.

6. In apparatus of the character described,

electrode means adapted to discharge electric current to fuse metal of the surface of a workpiece thatis disposed at an angle to the horizontal, a second electrode means adapted to discharge electric current against a substantially horizontal surface to deposit metal to progressively cox er said first mentioned surface, a nonconsumable electrode adapted to discharge electric current against the rising surface of the deposited metal, said non-consumableelectrode, said second electrode means and said first electrode means being mounted for vertical movement as a unit, means for indicating the characteristics of the discharge from'said non-consumable electrode, and means for vertically moving said non-consumable electrode, said second elec' trode means and said first electrode means as a unit to maintain the discharge from said nonconsumableelectrode at established characteristics. Y

'7. In apparatus of the character described, electrode means adapted to discharge electric current to fuse the surface of a workpiece that is disposed at an angle to the horizontal, a second electrode means adapted to discharge electric current against a substantially horizontal surface to deposit metal to progressively cover said first mentioned surface, a non-consumable electrode adapted to discharge electric current against therising surface of the deposited metal,

said non-consumable electrode, said second electrode means and said first electrode means being mounted for vertical movement as a unit, motor operated means for vertically moving said nonconsumable electrode, said second electrode means and said first electrode means, vertically as a unit, and control means for said motor operated means operative to control the operation of said motor operated means to maintain a discharge of predetermined character from said non-:consumable electrode.

8. In apparatus of the character described, electrode means adapted to discharge electric current to fuse the surface of a workpiece that is disposed at an angle to the horizontal, a nonconsumable electrode mounted for vertical movement as a unit with said electrode means adapted to discharge electric current against a substantially horizontally disposed surface, means for indicating a characteristic of the discharge from the non-consumable electrode, and means for vertically moving said non-consumable electrode 1 and said electrode means as a unit to maintain the indicated characteristic at a predetermined value. I

9. In apparatus of the character described, electrode means adapted to discharge electric current to fuse the surface of a workpiece that is disposed at an angle to the horizontal, a nonconsumable electrode mounted for vertical movement as a unit with said electrode means adapted,

to discharge electric current against a substantially horizontally disposed surface, controllable motor operated means for vertically moving said electrode means and said non-consumable electrode as a unit, and means controlling said motor operated means in accordance with the characteristics of the discharge from said non-consumable electrode to maintain said discharge at -a predetermined value.

ROBERT K. HOPKINS. 

